In the recent years flat panel display devices are more frequently developed to replace conventional cathode-ray tube (CRT) units; in particular, LCD devices are becoming commercially attractive more and more due to their advantage such as light weight, thinness, low power consumption and the like.
As one typical prior known LCD devices, an light transmissive active-matrix LCD device will now be described herein which comes with a plurality of switch elements each of which is at a respective one of picture elements. The active-matrix LCD device includes a liquid crystal layer as held between an array substrate and a opposed substrate with orientation films being provided between the liquid crystal layer and any one,of such substrates. The array substrate has, on a transparent insulative substrate made of glass, quartz or the like, a plurality of signal lines and a scanning lines arranged in a matrix form. At each of such crosspoints, a thin film transistor (abbreviated to "TFT" hereinafter) made of semiconductor thin film such as amorphous silicon (referred to as "a-Si:H") is connected to the lines. TFT has a gate electrode electrically connected to a corresponding one of the scanning lines, a drain electrode electrically connected to a corresponding signal line, and a source electrode electrically connected to a transparent conductive material constituting an associated pixel electrode, which material may be indium-tin-oxide (ITO).
The opposed substrate is constituted from a glass substrate on which an opposed electrode made of ITO is disposed; where displaying of color images is required, a color filter layer will be additionally provided thereon.